Detachable platen mounting for typewriting or like machines



1951 H J HART ET AL 2,542,868

DETACHAB LE PLATEN MOUNTING FOR TYPEWRITING OR LIKE MACHINES Filed Jan.51, 1949 2 Sheets-Sheet l INVENTORS HENRYJI HART BY WILLIAM H. KUPPERFeb. 20, 1951 H. J. HART ET AL DETACHABLE PLATEN MOUNTING FORTYPEWRITING OR LIKE MACHINES 2 Sheets-Sheet 2 Filed Jan, 31, 1949Patented Feb. 20, 1951 DETACHABLE PLATEN MOUNTING FOR TYPEWRITING ORLIKE MACHINES Henry J. Hart and William H. Kupper, West Hartford,Conn.,.assignors to Royal Typewriter Company, Inc., New York, N. Y., acorporation of New York Application January 31, 1949, Serial No. 73,802

2 Claims.

This invention relates to a detachable platen mounting for typewritingor like machines.

In using office machines, particularly typewriters, for difierentkindsof work it frequently is desirable to replace a relatively hardplaten with a relatively soft platen, or vice versa, according towhether maximum quietness of operation, or maximum manifolding capacityis desired. The average operator is not able to, or will not take thetrouble to make such a change unless it can be ,done without usin anyappreciable mechanical aptitude.

It has been proposed heretofore to provide a removable platen mountingconstruction in which one end of the platen is journalled in a support,e. g. a carriage end plate, in such manner that it may be released so asto permit the platen to be tipped or tilted about its other end, andthen moved endwise to disengage its other end from its supporting andjournalling means, thus enabling a platen having the desired differentcharacteristics to be substituted by a reverse operation. Examples ofprior constructions embodying this basic concept are disclosed in thepatent to Myers 1,496,940, and Handley 2,028,280.

An object of the present invention is to provide a detachable platen andmounting or supporting means therefor of the general class referred toabove, but which is of improved construction enabling the platen to beremoved from or inserted in operative position more easily than has beenpossible heretofore.

A representative construction embodying the invention in a preferredform is illustrated in the accompanying drawings, in which:

Figure 1 is a fragmentary front elevational view, partly in section, ofa typewriter carriage and removable platen embodying the invention, theplaten being shown in its normal position in dotted lines, and beingshown in full lines in the position to which it may be tilted for beingremoved from the carriage;

Figure 2 is an exploded perspective detail view showing a line-spacingspindle and associated parts;

Figure 3 is a vertical cross section on the line 3--3 of Figure 6;

Figure 4 is a detail fragmentary view, partly in section on theirregular "line 44 of Figure 5, and partly in elevation, drawn on anenlarged scale, showing the right-hand end of the removable platenlocked in normal operative position in the carriage;

Figure 5 is a cross section on the line 5--5 of Figure 4; and

Figure 6 is a vertical longitudinal sectional view of the left-hand endof the platen, the associated supporting part of the carriage andlinespacing mechanism.

In the drawings illustrating a preferred embodiment of the inventionthere is shown a typewriter carriage A on which is supported for easyremoval and replacement a platen or cylinder B. In most respects thecarriage is of standard or well-known construction and includes endplates l and 2 on which the platen is journalled at its opposite ends.The arrangement is such that the right-hand end of the platen may bereleased from its journal support and tipped upwardly from the normaldotted line position to the full line position shown in Figure 1, andthen withdrawn toward the right so as to disassociate the left-hand endof the platen from its journal support on the carriage end plate I.

At its right-hand end the platen is provided with a hub 3 secured to theplaten by screws, one of which is shown at l in Figure 4. A stub shaft 5is secured to the platen hub 3 by set screws 6. The outer end of th stubshaft 5 is equipped with a finger knob I having a hub 8 secured to theshaft 5 by means of set screws 9. Between the platen hub 3 and the knobhub 8 is a bearing sleeve II! in which the platen shaft 5 is freelyrotatable. The sleeve [0 is formed with :an exteriorly grooved part IIadapted to be received in an open-end seat l2 in the carriage end plate2, the arrangement being such that the sleeve Il] may be inserted in theseat 12 from above, and removed from the seat by upward swingingmovement from the dotted line position to the full line position shownin Figure 1.

Normally the sleeve I0 is held in the position shown in Figure 4 andshown in dotted lines in Fi ure l by a retainer or latch l3. The latchI3 is so constructed and arranged as normallyto maintain the sleeve l0firmly in its operative position, but so as to be releasable readily forenabling the right-hand end of the platen to be tipped upwardly forremoval. In the: form shown, the latch I 3 is pivoted as at M on thecarriage end plate 2, and is provided with a finger piece I5 and with acam face I 6 adapted to engage the sleeve I 0 and press it firmly intoits seat 12 when the latch I3 is swung from the position shown in dottedlines in Figure 5 to the position shown in full lines in this figure.

In order that the latch l3 maybe held releasably in its operative orlatching position it is provided with a sprin finger detent I7 adaptedto engage a fixedpin l8 carried by the end plate 2. Preferably thedetent I1 is formed integrally with a shroud I9 secured to the latch I3by screws passing through slots 2i in the shroud and having threadedengagement with the latch 53. The shroud provides a cover for the platenhub 3, the latch I3 and the inner end of the sleeve I ii, therebyenhancing the appearance of the assembled parts adjacent to theright-hand end of the platen. The mounting of the shroud I9 on the latchI3 by the screw and slot connections 2Il2I enables the detent finger I!to be adjusted so as to determine the latched position of the retainerI3 as that in which the proper pressure will be exerted upon the bearingsleeve ID.

Th left-hand end of the platen is journalled on the carriage end plate Iand is operatively associated with line-spacing mechanism by which theplaten may be turned through one line space V bearing sleeve 24 extendsthrough the carriage end plate I and has its outer end threaded toreceive a nut 25 which cooperates with a shoulder 26 on the sleeve 24for clamping the sleeve in place. i

A hollow spindle 2I journalled in the sleeve 24 extends outwardlythrough an opening 28 in the ear 23 and into the hub 29 of a finger knob30, set screws 3I securing the hub 23 and spindle 2'I infixed assembly.The hub 29 is formed with a reduced part 32 by which the hub isjournalled in the opening 28 of the car 23. As will be described later,turning of the knob and the spindle 2! serves to rotate the plateneither a line space or a fractional line space as may be desired.

Mounted to turn freely on the spindle 21 and located 'to the right ofthe bearing sleeve 24 is a line spacing ratchet wheel 33 which is fixedto a line spacer coupling ring 34 to be described in more detailhereinafter.

The ratchet wheel 33 is adapted'to be operated by known mechanismincluding a combined carriage return and platen line spacing lever (notshown) and connections between the lever and the ratchet wheel 33including a pawl 35 carried by a rockable lever 36 adapted to beactuated by the line-spacing lever (not shown) for causing the pawl 35to engage the ratchet wheel 33 and turn it about the platen axis. Aselector shield 31 equipped with a finger piece 38 is mounted foradjustment around the ratchet Wheel 33 to enable th operator to selectthe number of complete line space increments through which the platen isto be turned upon an operation of the line-spacing lever (not shown).

New and improved means are provided for coupling the spindle 27 to theplaten B, and for coupling the platen to the line spacing ring 34.

As shown in Figure 6, the left end of the platen B is provided with ahub 39 secured to the platen by screws 40. The hub '39 is formed with an1 axial opening M, the outer end of which is spindle 2! are centeredwith respect to each other.

The hub 39 is formed with cylindrical outer end part 43 which receivesfor sliding movement a disk part 44 to which are fixed three guide pins4 45 extending through bearings or bushings 45 secured in holes 41 inthe platen. Springs 48 positioned in the holes 41 are arranged topress-upon collars 49 respectively on the pins 45 for urging the pinsand the disk part 44 toward the left as viewed in Figure 6.

A split ring 55 formed with a finger 5i is spring fitted into anundercut recess 52 in the disk part 44 as best shown in Figures 3 and 6.When the parts are assembled, the ring 55 is fast with the disk part 44and the finger 5i projects inwardly through a slot 53 in the hub 39 soas to intersect th platen axis.

In order thatthe disk 44 may be operatively coupled to the line -spacingring 34 in rotational driving relationship, the disk is formed withthree circumferentially spaced radial extensions 54 ----54 -54 which aretoothed respectively at 55 55 and 55 so as to be engageable withinternal teeth 55 on the ring 34. The teeth .55, 55 and 55 are tapered,as best shown in Figure 6, to facilitate movement of the disk 44 fromthe left of the toothed part 56 of the ring 34 to a position in whichthe toothed part of the ringsure rounds and is engaged by the teeth onthe disk 44.

In order that the disk 44 may be disengaged from the toothed part of thering 34 when the platen is journalled in its normal position, and inorder that the platen may be turned through a fractional line spaceincrement, a rod" or pin 51 is mounted for sliding movements in thehollow spindle 2i and has its inner end arranged "to engage th finger 5|carried by the disk 44 so that the disk may be pushed toward the rightin Figure 6 to remove it from engagement with the ring 34. Fixed to theouter end of therod 51 is a finger button 58. A sleeve 59, fixed to therod 51 adjacent to the button 53, is formed with an external flang 69which is adapted to engage an internal flange 6| on the knobhub 29 forlimiting the outward movement of the rod 51 and the button 58 under theurge of a spring 62 interposed between the button 58 and the left end ofthe hub 29. Normally the spring 62 holds the button 58 and rod 51 in theposition shown in Figure 6 in which the right-hand end of the rod 51 isdisengaged from the finger 5| carried by the fractional line spacingdisk 44. By pressing the button 58 toward the right, the rod 5'! will becaused to push the finger 5| and the disk 44 to the right to disengagethe teeth 55, 55 and 55 from the teeth 56 of the ring 34.

The mechanism for coupling the finger knob and the spindle 21 inrotational driving relationship with the platen B includes a radial arm53 secured to the inner end portion of the spindle 21 and having itsouter end bent to provide a V broad fiat thin tongue 64 extendingparallel to the platen axis and toward the end plate 2. The

stantially tangentially to imaginary circles concentric with respect tothe spindle axis. When the parts are in the assembled relationship shownin Figure 6 the tongue 64 projects through the general plane of theteeth 55 on the ring 34, and into one of three openings 65, 55 and 35 inthe disk 44. The openings are spaced circumferentially from each otherand are displaced angularly with respect to the disk extensions 54 54and 54 so that each opening lies midway between two adjacent diskextensions. show the parts so positioned that the tongue 54.

projects into the disk opening 65*, whereby when the spindle 21 and arm63 are rotated, the tongue The drawings 64 will drive the diskandhe'nc'ethe plate'nro tationally. 1

When it is desired to eifect' only a fractional line spacing movement ofthe platen, the button 58 is pushed inwardly to disengage the disk Mfrom the ring 34 as described above, enabling the knob ac to turn theplaten through the medium of the spindle 27 and the .arm 63 while theline spacing ring 34 and ratchet wheel 33 remain stationary.

A particular advantage provided by the present invention is the easewith which the platen maybe tipped and otherwise manipulated for placingit in or removing it from its normal position. This advantage resultsmore particularly from-the novelformation and arrangement of the holes65 65 and 65. and the tongue 56. As shown in Figure 3, each of the holes65*, 65 and 65 is substantially reotangular'and includes two opposedsides which extend parallel to one ananother and substantially orgenerally radially with respect to the axis of the disk M. These twosides of each hole are so spaced as snugly or closely to engage orembrace the two longitudinally extending edges of the tongue 66. Theother two sides of each of the openings et 55 and 55 are mutuallyopposed and are spaced from each other so as to provide substantiallymore clearance with respect to the fiat surfaces of the tongue 64 thanwould be required for accommodating the tongue when the spindle 2? andthe platen are axially aligned. In a general way, the inner and outersides of the openings are tangent to imaginary circles concentric withthe axis of the disk 44.

The platen can most easily be placed in its operative position by firstturning the spindle 21 to place the tongue 64 above the axis of thespindle 2'! as shown in Figures 1 and 6, and then inserting the tiltedplaten endwise to the left to the position shown in full lines in Figurel in which the tongue 64 is received by the opening 55 The ampleclearance between the broad faces of the tongue 65 and the inner andouter sides of the opening 55 makes it possible for the platen to beinserted in the tilted position, and then swung downwardly to horizontalposition without any binding between the tongue 64 and the sides of thedisk opening 65 Because of the angularly displaced positions of theopenings 65*, 65 and 65 with respect to the disk extensions 54 54 and5%, each of the openings is disposed diametricall opposite one of thedisk extensions. For example, as shown in Figure 4-, the disk opening 55is diametrically opposite the extension 54. After the platen has beenplaced in the tilted position with the tongue e4 extending into theopening th and is then tilted, the teeth 55 on the extension 5 t whichwill move more than any other part of the disk 54 during tipping of theplaten to its horizontal position, will extend and move parallel to theadjacent teeth 55 on the ring 34. This will enable the teeth 55*" to bemoved into mesh with the adjacent teeth 55 without substantial binding,the tipping of the platen not bringing about any substantial lack ofparallelism between the teeth 55 and the adjacent teeth 55. The teeth55% and 55 on the disk 34 will be somewhat out of parallelism with theadjacent teeth 55 during the tipping movement, but the teeth 55 and 55are located at or so close to the axis of tipping that the rela tivemovement between these teeth and the teeth 56 is small, and noappreciable binding or interference to tipping can be noticed.

The construction illustratedand described herein embodies the inventionin a preferred form but it is intended that the disclosure beillustrative rather than definitive of the invention. The inventionisdefinedin the claims.

We claim:

1. In a typewriting or likemaohine, a support having spaced end members;a spindle journalled in one of said end members and having an inner endportion projecting towards the other of said end members; a fractionalline spacing mechanism including a ringconcentric with and spacedradially from said spindle and formed internally with teeth extendingparallel to the spindle axis; an arm fast with said spindle andextending radially outwardly therefrom and having at its outer end aflat broad thin tongue projecting parallel to the spindle axis throughthe general plane of said ring and towards said other of said endmembers, and having its broad faces tangent respectively to circlesconcentric with said spindle a cylindrical platen having at one of itsends means cooperable with said spindle inner end portion for centeringsaid platen end with respect to said spindle; a disk on said platen endhaving three radial extensions equally spaced circumferentially fromeach other and having outer toothed portions adapted to mesh wit-h theinternal teeth on said ring, said disk also having three openingsequally spaced circumferentially from each other and displaced angularlyabout the disk axis so that there is one such opening angularly midwaybetween each two adjacent disk radial extensions, any one of saidopenings being adapted to receive said tongue for coupling said spindleto said platen in rotational driving relationship, each of said openingsbeing substantially rectangular and having two opposed substantiallyradial sides adapted snugly to embrace opposite edges of said tongue,the other two sides of each opening being spaced radially from eachother by substantially more clearance than is required for accommodationof said tongue when said spindle and platen are axially aligned; an openend bearing sleeve seat in said other of said end members; a bearingsleeve for journalling the other of said platen ends and beingreceivable in said seat; and a releasable retainer for holding saidsleeve in said seat, releasing of said retainer permitting said platento be removed from said support by tilting the platen about said one ofits ends and then moving it longitudinally of its axis.

2. In a typewriting or like machine, a support having spaced endmembers; a spindle journalled in one of said end members and having aninner end portion projecting towards the other of said end members; afractional line spacing mechanism including a ring concentric with andspaced radially from said spindle and formed internally with teethextending parallel tothe spindle axis; an arm fast with said spindle andextending radially outwardly therefrom and having at its outer end afiat broad thin tongue projecting parallel to the spindle axis throughthe general plane of said ring and towards said other of said endmembers, and having its broad faces tangent respectively to circlesconcentric with said spindle; a cylindrical platen having at one of itsends means cooperable with said spindle inner end portion for centeringsaid platen end with respeot to said spindle; a disk on said platen endhaving three radial extensions equally spaced circumferentially fromeach other and having outer toothed portions adapted to mesh with theinternal teeth on said ring, said disk also having three openingsequally spaced ciroumferentially from each other and displaced angularlyabout the disk axis so that there is one such opening angularly midwaybetween each two adjacent disk radial extensions, any one of saidopenings being adapted to receive said tongue for coupling said spindleto said platen in rotational driving relationship, each of said openingsbeing substantially rectangular and having two opposed substantiallyradial sides adapted snugly to embrace opposite edges of said tongue,the other two sides of each opening being spaced radially from eachother by substantially more clearance than is required for accommodationof said tongue when said spindle and platen are axially aligned; andmeans journalling the other of said platen ends in said other of saidend members in a manner to permit releasing of said other of said platenends and tilting of said platen to disengage it from said spindle andsaid tongue.

HENRY J. HART. WILLIAM H. KUPPER.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Myers June 10, 1924

